This invention relates to a seat cover fastening system for vehicle seats, and particularly for fastening a seat cover to a support frame where a covered pad or cushion is placed on top of the frame and held thereon by a trim strip which engages both the seat cover and the support frame. Examples of seat cover fastening systems in the prior art are illustrated in U.S. Pat. No. 3,981,534 and U.S. Pat. No. 4,526,420.
In U.S. Pat. No. 3,981,534, an extruded J-shaped plastic welt is adapted to be sewn to the seat cover. The vehicle seat pan has an inverted U-shaped peripheral flange. The long leg of the welt cross-section is first sewn to the seat cover. The seat cover is stretched over the seat pad and seat pan and the short leg of the welt cross-section is hooked over upwardly and inwardly projecting tabs struck out of the material of the seat pan outer peripheral flange. This design has the disadvantage that once the seat cover is installed, the welt cannot be removed.
Another seat cover fastening system, described in U.S. Pat. No. 4,526,420, involves the use of an endless fixing band made of rigid, yet elastic material such as ABS resin. The edge of the seat material is folded over and sewn, forming a tube through which the band is inserted. The seat cover is placed over the seat to which it is to be attached, and the fixing band is turned outside in, catching a downward extending perimeter of the seat frame. This design has the advantage that it is removable by flipping the band inside out. However, it has the disadvantage of requiring a continuous band hoop shape going around the seat and is therefore limited to use on a bag shape seat cover. Finally, it has the disadvantage that it is possible for the band to inadvertently flip downward and off of the frame.
It is therefore an object of the present invention to provide a seat cover fastening system providing uniform cover retention at minimal cost and minimal expenditure of labor during assembly. It is a further object of the present invention to provide a seat trim attachment strip which will lock the seat cover in place on the seat frame. It is a further object of the present invention to provide a seat trim attachment strip that allows for disengagement with the seat frame only when desired for repair or seat cover replacement.
It is yet further an object of the present invention to provide a seat trim attachment strip that is easily assembled to a seat cover and easily assembled to the seat frame.
The improved fastening system of the present invention comprises the use of a seat trim attachment strip sewn to the periphery of seat cover material. The trim attachment strip has a unitary body having a base portion and a plurality of pairs of side-by-side barbed projections, spaced apart along the base portion of the strip. The side-by-side projections are biased toward a spaced apart position, and can be flexed toward each other. Each projection terminates in a barb shaped tab which projects transversely outward from the projection. Each pair of projections is spaced to correspond to an elongated aperture or slot of predetermined width in the underside of a vehicle seat frame. The barbed tabs are dimensioned relative to the slot width and legnth such that when the projections are inserted into the slots shoulders on the barbed tabs engage the frame to prevent movement of the tabs in the projection in an opposite direction.
In operation, the flange portion of the trim attachment strip is sewn to the periphery of a properly dimensioned piece of seat cover material. The seat cover is then placed over the seat cushion which rests on the seat frame. The barbed tabs are then pushed through corresponding slots in the frame underside thus securing the cover to the frame. As the spaced apart side-by-side projections are puhsed into the slot, the projections are flexed toward each other narrowing their width thus allowing insertion through the slot. Once the retention tabs have cleared the frame, the projections snap back to a spaced apart relation and the retention tabs prevent withdrawal of the projections in the opposite direction, thus securing the seat cover to the frame.